Perennial herb with a tuberous rootstock, much-branched from the base with numerous, erect stems, these sometimes simple in shorter forms but usually also more or less branched, 15–50 cm. tall; stem and branches quadrangular above, terete below, striate, moderately to rather densely furnished with upwardly directed or more or less patent whitish hairs. Leaves opposite or the upper occasionally ternate, elliptic or narrowly elliptic, 2–7.2 × 0.4–2.5 cm., gradually or more abruptly narrowed at base and apex, more or less acute, moderately to densely furnished on both surfaces with appressed hairs, rarely sublanate. Inflorescence cylindrical, 2–12 × 1.5–2 cm., dense, the axis densely white-pilose, sessile or with a peduncle up to 4 cm. long. Bracts deltoid-ovate, 5–6 mm. long, subglabrous, ciliate or sparsely (the midrib sometimes more densely) pilose, membranous except for the greenish midrib, which is excurrent in a long more or less pilose arista. Bracteoles very similar, not falling with the perianth, the arista about half the length of the lamina. Tepals all rather narrowly lanceolate, narrowly hyaline-margined, obscurely 3–5-nerved in the central green portion, more or less densely pilose with fine, patent or subpatent greenish-white hairs; outer 2 tepals 7–10 mm. long, the inner 3 gradually less pilose and slightly more broadly margined. Stamens 3–4 mm. long, the filaments densely pilose below; pseudo-staminodes 1–2 mm. long, flabellate with reflexed, densely hairy margins, dorsal scale absent or very small and concealed in the marginal hairs. Ovary obpyriform, c. 1 mm. long, with a faint apical keel; style slender, 3–4 mm. long. Ripe capsule oblong-ovoid, c. 3 mm. long; seeds oblong-ovoid, c. 2.75 mm. long, brown, shining, faintly reticulate.
